Project Summary Background: The role of the family flows through many paths to impact children's health. Children's interactions with their families are affected by chronic illness, and chronic illness management requires family support to optimize outcomes. Positive family interactions also reduce the negative effects of environmental stressors on children's well-being. In recognition of the family's important role, new PROMIS measures include Family Belonging, reflecting the child's feelings, beliefs, and experiences as a member of the family, and Family Involvement, reflecting the consistency and quality of the child's interactions with family members. Because these new measures were primarily developed in a general pediatric population, additional evidence is needed before they can become widely accepted in clinical care or research with chronically ill children. Objective: To demonstrate clinical utility and validity of these emerging family-focused PROMIS measures from a socioeconomically diverse sample of chronically ill children and their parent-proxies. Building on the co- Principal Investigators' prior work with pediatric chronic illness and PROMIS measure development and validation, this longitudinal study of children with sickle cell disease, asthma, and type 1 diabetes will 1) evaluate the content validity and clinical utility of the new Family Belonging and Family Involvement measures, 2) determine reliability and convergent/discriminant validity of child and parent-proxy reports of these measures, 3) explore responsiveness to change and estimate clinically significant change, and 4) describe how child and parent-proxy reports of family belonging and family involvement change over time, by disease status, and with environmental stressors. Research Plan: Qualitative methods will be used to assess the measures' content validity and their clinical utility. From emergency department and routine clinic visits at two large Midwestern children's hospitals, we will also enroll 510 children 5-17 years old with sickle cell disease, asthma, or type 1 diabetes and their parent(s), obtaining consent for medical record abstraction and surveys (PROMIS domains, sociodemographics, and disease status). Surveys will be administered using standard methods at key time points, including in the emergency department (for an acute disease exacerbation), at 1-3 months after the emergency department visit, and every 6 months for 3 years, resulting in a rich longitudinal dataset of 14 PROMIS domains as reported by children and parent-proxies. Analyses will include Cronbach's alpha, comparisons of variance matrices, and mixed effects models examining how these family-focused measures change over time, by disease type, and with environmental stressors. Significance: Completion of this project will increase the level of evidence for these measures as outlined in the PROMIS Instrument Maturity Model, ensuring that NIH's initial investment in the PROMIS Family Belonging and Family Involvement item banks will result in ?go-to? measures of these concepts across pediatric chronic conditions. Findings will support the broad incorporation of PROMIS measures into clinical care and research for chronically ill children.